You know what really floats my boat? The Dead Sea. You know, because of how salty it is, so that the water is better able to keep boats afloat.
...Oh wait, "floats my boat" is a figure of speech, isn't it? And besides, I don't even have a boat.
Well, anyway, one thing that really floats my boat is seeing a rainbow in the sky. Especially if it had been raining really hard prior to that. A couple of days ago I was driving home when I saw one not only in the sky, but all across the road because rain was still falling all around nearby. My mouth hung open and my eyes were wide in amazement all the way back home, and I kept saying thing about how wonderful this was and how beautiful everything looked. And yes, I was completely sober, in case you were wondering... otherwise I wouldn't have been driving, we hope.
In fact, a lot of things that float by boat revolve around seeing certain things in nature. Also on the list are being surrounded by trees and seeing lots of stars in the night sky (which rarely happens given the light pollution in my hometown).
Also nowadays I get really excited, perhaps a bit overexcited, when I hear good news about a job or a college I'm applying to. And at my current job working at a shoe store, it really floats my boat to see a customer really happy about a pair of shoes I found for them (especially if they don't see their size in the style they like and I grab it from the store's back storage).